From: Niraj kumar (niraj17_at_gmail.com)
Date: Wed Jun 29 2005 - 05:48:20 CDT
Hi Dave ,
We are seeing this problem on a 32 bit system .
Is there any reason (in your opinion) for this to appear on 32-bit ?
I just tested the latest code from NAMD (from cvs) and charm++ (from nightly
build) and it is still there . The stack trace (from core) looks like this :
(gdb) where
#0 0x0823ef18 in _int_malloc ()
#1 0x0823e535 in mm_malloc ()
#2 0x0824009d in malloc ()
#3 0x08240296 in malloc_nomigrate ()
#4 0x082a43f8 in CmiAlloc ()
#5 0x082a200c in PumpMsgs ()
#6 0x082a21ed in CmiGetNonLocal ()
#7 0x082a37e1 in CsdNextMessage ()
#8 0x082a38ac in CsdScheduleForever ()
#9 0x082a384f in CsdScheduler ()
#10 0x080d4884 in BackEnd::init ()
#11 0x080d1961 in main ()
Regards
Niraj
On 6/28/05, David Kunzman <kunzman2_at_uiuc.edu> wrote:
> There does not seem to be a prototype for this function (and a few
> others). As a result, the compiler is assuming the return type of the
> function is an "int". When the compiler (icc in the case we were
> looking at) does the cast, it tries to convert the "int" that was
> returned (which is really a 64-bit pointer) into a "char*". Since the
> compiler "thinks" the returned value is only 32-bits, it is sign-extends
> the 32-bit value to fit the 64-bit register which wipes out the upper
> 32-bits of the pointer making it invalid. A fix should be checked in soon.
>
> Dave Kunzman
>
>
> Brian Bennion wrote:
>
> >Hi Tim,
> >I saw your posting on the namd wiki and want you to know that I to have
> >seen this problem or one very similar in mm_mallac. David Kunzman
> >(charm++ developer) worked on it for a couple of days last week.
> >
> >I do not know what the final results were, other than the compiler makes
> >some default assumptions about casting a void * to a char *. It instead
> >casts it to an int and wipes out half of the memory address. So what is
> >actually returned is entirely bogus.
> >
> >What compiler are you using?
> >
> >Brian
> >
> >
> > ************************************************
> > Brian Bennion, Ph.D.
> > Bioscience Directorate
> > Lawrence Livermore National Laboratory
> > P.O. Box 808, L-448 bennion1_at_llnl.gov
> > 7000 East Avenue phone: (925) 422-5722
> > Livermore, CA 94550 fax: (925) 424-6605
> >************************************************
> >
> >
> >
>
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